<div>I always advocatred SL (Sainte-Lague) over dH (d'Hondt) for party list PR, because, if you're using PR it's because you want proportionality, and if you want proportionality, then you want SL.</div><div> </div>
<div>Then, more recently, I said that, since I don't think that we need PR anyway (though I have nothing against PR), d'Hondt would be fine, especially since it guarantees a seat majority to a vote majority.</div>
<div> </div><div>But now I feel that I was mistaken to say that. For two reasons:</div><div> </div><div>1. For fair inclusion, there should be no threshold. d'Hondt will disproportionately exclude small parties. That matters, because PR can only be justified, in comparison to a good single-winner method, if there's no significant split-vote problem. You shouldn't have to worry that you need to vote for a compromise because your favorite party might not have enough votes to win a seat. That problem is, of course, worse in d'Hondt than in Sainte-Lague.</div>
<div> </div><div>2. In PR, the idea is that you don't have to compromise in your voting, because you can just elect representatives (members of parliament congress-members, etc.) of your party to parliament or congress, and _they_ can do the compromising, when necessary--but only when necessary.</div>
<div> </div><div>But how true is that in d'Hondt? Not very. </div><div> </div><div>Say your favorite party is significantly smaller than the ones that are in major contention in parliamentary voting. If you vote for your party, and it's a small party, d'Hondt will give it _significantly_ less representation per person, as compared to the larger parties. So your favorite party won;t have many seats with which to support coalitions. If compromising, coalition-support, are necessary, then you'd do better, in the d'Hondt PR election, to give your vote to a big party, so that you can thereby add more seats to the coalition that you want to support.</div>
<div> </div><div>That's no good. d'Hondt fails FBC, if FBC were extended to PR methods.</div><div> </div><div>No, to fulfill the purpose of PR, Sainte-Lague, virtually free of size-bias, is the method to choose. SL also puts every party as close as possible to its correct proportional share.</div>
<div> </div><div>Yes, SL isn't _entirely_ unbiased. Its unbias depends on the assumption (at least in the regions of interest) of a uniform probability distribution for parties, with respect to the scale of party vote totals. That assumption isn't really correct. There are more likely to be more small parties than large. The distribution-curve is most likely a decreasing function. From that, one would expect Sainte-Lague/Webster to be _very slightly_ large-biased. That's probably true of Largest-Remainder too. Both of those methods are strictly unbiased only if that probability-distribution is flat, within the areas of interest.</div>
<div> </div><div>But that bias isn't enough to matter, and doesn't bother me at all.</div><div> </div><div>For example, even when that probability distribution is assumed flat, for the vote or population range between each pair of consecutive whole numbers of quotas (whole number values of the quotient of votes or population by whatever divisor is being tried) Hill's method is significantly small-biased, where, under that assumption, Webster (Sainte-Lague) is completely unbiased. But, even so, Hill is only as biased as follows:</div>
<div> </div><div>Consider a small party whose quotient, by the final divisor, is equally likely to be anywhere between 1 and 2. And consider a large party whose quotient is equally likely to be anywhere between 53 and 54.</div>
<div> </div><div>The small party's expected s/v is only 1.057 times greater than the large party's expected s/v.</div><div> </div><div>And that's with Hill's blatant small-bias. So Websters particularly slight large-bias wouldn't matter at all.</div>
<div> </div><div>There are seat allocation method that have been proposed, by Warren Smith and me, that seek more perfect unbias, without the assumption stated above.. But they're more complicated, &/or without precedent. I cl;aim that SL is quite good enough, and should be the only method used for allocation of seats to fixed districts; or for allocation of seats to parties in list-PR.</div>
<div> </div><div>Well, maybe later, at some point, people might be interested in considering those more perfectly unbaised methods.</div><div> </div><div>Anyway, I emphasize that, in the United States, the voting system is incomparably more important than the apportionment method.</div>
<div> </div><div>However, it's also true that apportionment has been very fiercely fought, and demonstrating that Hill is biased, even in the amount that I stated above, and showing where a large state loses a seat because of Hill, might show the people in that large state that Hill is unfair. And that will show people that our current ways of doing things can be wrong. And that will make people more willing to look at the wrongness of Plurality. So I feel that Hill's small bias should be publicized, especially when it can be shown to have recently taken a seat away that a large state should have.</div>
<div> </div><div>Hill's method, currently used for U.S. House of Representatives apportionment, is usually known by the (incorrect) name of "Equal Proportions".</div><div> </div><div>Mike Ossipoff</div><div>
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